those permax motors arent for sale in the usa anymore, tower hobbies discontinued them a year or so ago.

the speed 400s if you look at my motor post from last year, turn more rpms then the the black capped suntechs and of course the white capped ones. i don't have a dyno, never ran them in a tiger hull, but in a pershing and in the walker bulldog, the tank flys and pulls like a truck.

tigers run close to scale speed with the white motors with metal tracks. if you want even more torque you're looking for gearing that no motor can deliver. the new asiatam gearboxes coupled with speed400s will give you a little more speed with tons more torque.